The Maritime Union is calling for authorities to detain a cargo ship at the Port of Tauranga until all 14 problems relating to the crew and the boat's seaworthiness are fixed.
Australia's Maritime Safety Authority prohibited the Liberian-flagged Vega Auriga from using its ports after what it calls repeated breaches of international safety conventions.
Maritime New Zealand has detained the ship but says it is free to leave once 11 of the 14 problems identified have been resolved.
However, Maritime Union secretary Joe Fleetwood has labelled it 'a ship of shame' and said that was not good enough.
"It's a disaster that's been bumped off the Australian coast and pushed over here to New Zealand, you know we don't know what the 14 deficiencies that Maritime New Zealand are have found."
He said potentially the ship could have run aground on the New Zealand coast.
Mr Fleetwood said a representative of the International Transport Workers Federation was in the process of checking on the condition of workers and safety on board the vessel.
Maritime New Zealand said yesterday the ship should be able to leave port by lunchtime today, but that will now happen tomorrow.